目的 通过有限元分析模拟股骨近端仿生髓内钉（PFBN）远端动态锁定和静态锁定固定股骨转子间骨折的生物力学特性。 方法 采集1例成年男性志愿者髋关节至胫骨上段CT影像数据，应用Mimics 20.0和Geomagic 2013软件建立股骨三维模型，运用NX 12.0软件将股骨三维模型制作Evans Ⅰ型股骨转子间骨折模型，并参考常用内固定参数，分别建立4种股骨转子间骨折的PFBN固定模型：远端单横钉动态锁定（模型A）、单斜钉动态锁定模型（模型B）、单钉静态锁定模型（模型C）和双钉静态锁定模型（模型D）。采用Abaqus6.14软件加载分析内固定应力及骨折断端位移情况。 结果 在2 100 N载荷下，四种模型的应力峰值均位于主钉，其中主钉应力峰值最小的为模型D（161.9 MPa），较模型A（192.5 MPa）减少15.9%，较模型B（191.9 MPa）减少15.6%，较模型C（163.3 MPa）减少0.9%；固定螺钉应力峰值最大的为模型A（95.3 MPa），最小的为模型B（91.5 MPa），模型C和D的分别为91.5、92.2 MPa；内置物整体位移由大到小依次为模型A（10.14 mm）、模型B（10.10 mm）、模型C（10.09 mm）、模型D（10.05 mm），骨折端位移由大到小同样为模型A（0.125 mm）、模型B（0.121 mm）、模型C（0.110 mm）、模型D（0.098 mm）。 结论 相较于动态锁定，PFBN远端静态锁定可以增强内固定稳定性，并减少内固定应力集中情况的发生。 Objective To characterize the biomechanics of distal dynamic locking and distal static locking of proximal femur bionic nails (PFBN) in fixation of intertrochanteric fractures by a finite element analysis. Methods The CT image data from the hip to the upper tibia from an adult male volunteer were used to establish a three-dimensional model of the femur by Mimics 20.0 and Geomagic 2013 which was processed further into a model of Evans type I intertrochanteric fracture by software NX 12.0. With reference to the internal fixation parameters commonly used, 4 models of PFBN fixation were established: distal single transverse nail dynamic locking (model A), single oblique nail dynamic locking (model B), single nail static locking (model C) and double nail dynamic locking (model D). Abaqus 6.14 software was used to load and analyze the internal fixation stresses and displacements of fracture ends. Results Under a 2100N loading, the peak stress was located upon the main nail in the 4 models. The smallest peak stress upon the main nail was in Model D (161.9 MPa), decreased by 15.9% compared with model A (192.5 MPa), by 15.6% compared with model B (191.9 MPa), and by 0.9% compared with model C (163.3 MPa). The peak stress upon the fixation screw was the largest in model A (95.3 MPa), the smallest in model B (91.5 MPa), and 91.5 MPa and 92.2 MPa in models C and D, respectively. The overall displacements of the implants, in a descending order, were 10.14 mm in model A, 10.10 mm in model B, 10.09 mm in model C, and 10.05 mm in model D. Similarly, the displacements of fracture ends were 0.125 mm in model A, 0.121 mm in model B, 0.110 mm in model C, and 0.098 mm in model D. Conclusion Compared with dynamic locking, distal static locking of PFBN provides a better mechanical stability and reduces stress concentration upon internal fixation.
Abstract
Objective To characterize the biomechanics of distal dynamic locking and distal static locking of proximal femur bionic nails (PFBN) in fixation of intertrochanteric fractures by a finite element analysis. Methods The CT image data from the hip to the upper tibia from an adult male volunteer were used to establish a three-dimensional model of the femur by Mimics 20.0 and Geomagic 2013 which was processed further into a model of Evans type I intertrochanteric fracture by software NX 12.0. With reference to the internal fixation parameters commonly used, 4 models of PFBN fixation were established: distal single transverse nail dynamic locking (model A), single oblique nail dynamic locking (model B), single nail static locking (model C) and double nail dynamic locking (model D). Abaqus 6.14 software was used to load and analyze the internal fixation stresses and displacements of fracture ends. Results Under a 2100N loading, the peak stress was located upon the main nail in the 4 models. The smallest peak stress upon the main nail was in Model D (161.9 MPa), decreased by 15.9% compared with model A (192.5 MPa), by 15.6% compared with model B (191.9 MPa), and by 0.9% compared with model C (163.3 MPa). The peak stress upon the fixation screw was the largest in model A (95.3 MPa), the smallest in model B (91.5 MPa), and 91.5 MPa and 92.2 MPa in models C and D, respectively. The overall displacements of the implants, in a descending order, were 10.14 mm in model A, 10.10 mm in model B, 10.09 mm in model C, and 10.05 mm in model D. Similarly, the displacements of fracture ends were 0.125 mm in model A, 0.121 mm in model B, 0.110 mm in model C, and 0.098 mm in model D. Conclusion Compared with dynamic locking, distal static locking of PFBN provides a better mechanical stability and reduces stress concentration upon internal fixation.
关键词
有限元分析/髋关节/骨折,应力性/股骨转子间骨折/股骨近端仿生髓内钉
Key words
Finite element analysis/Hip joint/Fractures, stress/Intertrochanteric fracture/Proximal femur bionic nail
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